The present application is directed to modes for jointly controlling the yaw and pitch of a dynamically balanced personal transporter.
Dynamically stabilized transporters refer to personal transporters having a control system that actively maintains the stability of the transporter while the transporter is operating. The control system maintains the stability of the transporter by continuously sensing the orientation of the transporter, determining the corrective action to maintain stability, and commanding the wheel motors to make the corrective action.
For vehicles that maintain a stable footprint, coupling between steering control, on the one hand, and control of the forward motion of the vehicles is not an issue of concern since, under typical road conditions, stability is maintained by virtue of the wheels being in contact with the ground throughout the course of a turn. In a balancing transporter, however, any torque applied to one or more wheels affects the stability of the transporter.
In accordance with preferred embodiments of the present invention, there is provided a method for providing yaw control for a balancing transporter that has two laterally disposed ground-contacting wheels. The method has the steps of receiving a user input of a desired yaw value; comparing an instantaneous yaw value with the desired yaw value to generate a yaw error value; processing the yaw error value to obtain a yaw command signal; and applying the yaw command signal in conjunction with a pitch command signal based on a pitch error in such a manner as to maintain balance of the transporter in the course of executing yaw control.
In accordance with further embodiments of the invention, the yaw command signal may include component terms quadratic in the pitch error and/or a function of a common wheel rotational velocity.
In accordance with yet further embodiments of the invention, a yaw controller is provided. The yaw controller has an input for receiving a user-specified yaw value and a summer for differencing an instantaneous yaw value from the user-specified yaw value to generate a yaw error value. The yaw controller also has a processor for generating a yaw command signal based at least on the yaw error value in conjunction with a pitch command signal based on a pitch error in such a manner as to maintain balance of the transporter in the course of executing yaw control. The input for receiving a user-specified yaw value may be wirelessly coupled to the processor, and may have a grip coupled to a user interface such that the grip is rotatable about an axis fixed with respect to the user interface. The grip may also include a magnet moveable with respect to a sensor coupled to the user interface.